Re: [linux-lvm] [Q]XFS + LVM Snapshot?

From: Andreas Dilger <adilger turbolabs com>

To: Sean Oh <oh linuxsecurity co kr>

Cc: linux-lvm sistina com

Subject: Re: [linux-lvm] [Q]XFS + LVM Snapshot?

Date: Sat Nov 17 16:21:02 2001

On Nov 18, 2001 02:59 +0900, Sean Oh wrote:
> Kernel: 2.4.15-pre4 with XFS patch ( linux-2.4-xfs CVS tree from SGI site)
> LVM: current - LVM CVS
>
> Patches applied: linux-2.4.11-VFS-lock.patch from LVM CVS
>
> *I can not mount the original FS and snapshot FS at the same time. If
> I unmount the origianal XFS FS and then mount the snapshot FS, it works,
> tough.
Yes, you need an XFS patch which does something with the filesystem UUID
in the snapshot. XFS has a feature which prevents the same filesystem
from being mounted more than once.
What they do to fix this is to create writable snapshots. What I would
rather they do is in the "duplicate UUID detection" code, allow mounting
of devices which are on read-only media (e.g. a snapshot).
Cheers, Andreas
--
Andreas Dilger
http://sourceforge.net/projects/ext2resize/http://www-mddsp.enel.ucalgary.ca/People/adilger/